ST. LOUIS – On a weekend trip that was a surprise anniversary gift for his wife, an outdoors-loving Air Force veteran ventured out with two of his sons for a hike on a remote trail. Clad only in light jackets and sweaters, the three apparently didn't know how rapidly the weather would turn ugly, and that proved deadly.

Searchers found the soaked bodies of 36-year-old David Decareaux and the two boys — ages 8 and 10 — on the Ozark Trail on Sunday, a day after Decareaux declined a passerby's offer of a ride back to the lodge where they had been staying, Reynolds County Sheriff Tom Volner said. The cold had killed them, he said.

Only the family's 4-month-old yellow Labrador retriever survived the hike. He was found near Decareaux, who died at the scene, and the two boys, who were declared dead at a hospital after hours of efforts to revive them failed.

The tragedy crushed Decareaux's father-in-law, Keith Hartrum, who described the family as tightly knit, "always on the go and adventurous."

"Dave was a great guy, a good father, son-in-law and husband," Hartrum told The Associated Press. "Those two boys were just precious — smart, very nice kids."

It was nearly 60 degrees Saturday morning when Decareaux and his sons set out on the popular trail that runs through a sparsely populated area of southeast Missouri. Decareaux was wearing only a light jacket, while one of his sons was clad in a fleece pullover, and the other a sweater, Volner said.

They were ill-equipped as the temperature sank into the 40s, and a storm that would drop 2 inches of rain set in, making the trail all but impassable.

Volner said there are no caves or other places of refuge along the trail. Although Decareaux had a cellphone and flashlight with him, both devices lost power at some point, his wife, Sarah, told the St. Louis Post-Dispatch on Monday.

A passer-by spotted the hikers more than three hours into their journey and asked if they needed a ride back to the Brushy Creek Lodge near Black, where Decareaux's wife and their three other children — ages 12, 4 and 2 — were staying. But Decareaux declined, telling the man they could make it back, the sheriff said.

"They just missed their turn back to the lodge," the sheriff said. "By that time, their light played out. You don't have any ambient light down here because there are no cities or towns. When it's dark you can't see the back of your hand."

Officials at the lodge called the sheriff's department about 7 p.m. Saturday, concerned that the hikers had not returned. A search involving more than 50 volunteers on foot, horseback and in vehicles lasted until about 12:30 a.m. Sunday, when flash-flooding in creeks forced searchers to back off until daylight.

By then, it was freezing, and the temperature had dipped to the upper 20s by sunrise.

It wasn't long after that that the hikers' drenched bodies were found, their dog beside them. No autopsies were planned, and the deaths were attributed to hypothermia, Volner said.

Hartrum described Decareaux, who lived in Millstadt, Ill., as a doting father and spiritual man who had retired from the Air Force in recent years and was working with the Defense Department in a job he couldn't discuss, even privately. Karen Petitt, a spokeswoman at southwestern Illinois' Scott Air Force Base, said Decareaux worked there for the Pentagon's Defense Information Systems Agency.

Decareaux and his wife, Sarah, were married about 14 years ago after a chance meeting that was "love at first sight," said Hartrum, who lives near Waterloo, Ill. They made the most of his overseas assignments, using them to explore Europe over much of the past decade with his family, he said.

"They had a strong, good, healthy marriage," he said, noting the Decareaux was an experienced hiker "who just got caught up (last weekend) in a freak situation" that proved fatal.

Sarah Decareaux said prayer and her spiritual faith were helping her press on.

"We are a Christian family," she told the Post-Dispatch as she headed to a funeral home to make arrangements. "I know where they are now."